Festo VABF-S4-CB-VH Series, Instructions & Operating

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4.9 Monitoring and diagnostics
The vacuum generator has monitoring functions that enable early detection of malfunctions or faults
during operation.
–
Monitoring of process parameters (pressure value at vacuum connection, critical limits, evacu-
ation time t
E
, air supply time t
B
, process quality)
– Monitoring with the aid of diagnostic parameters è Tab. 15 Diagnostic parameters
– Fault detection and diagnostic messages è 10 Malfunctions
The monitoring functions are activated at the factory (except for monitoring of the evacuation and air
supply times). The monitoring of the evacuation and air supply times can be activated by setting the
critical limits evacuation time and air supply time.
4.9.1 Monitoring the process
The process quality shows information on the quality of the process with the air saving function active
è 4.8 Air saving function. The process quality is measured by calculating the vacuum decay rate (VDR
= Vacuum Drop Rate [kPa/s]) from hysteresis and leakage time (t
LE
). A reference variable of 50 kPa/s
is applied to the VDR. A process quality of 0% corresponds to the VDR of 50 kPa/s (100% = 0 kPa/s).
Example 1
– Hysteresis – 5 kPa = 25 kPa
– Leakage time = 3 s
Value Calculation Result
VDR 25 kPa
-
3 s 8.33 kPa/s
Reference to 50 kPa/s (VDR) 8.33 kPa/s
-
50 kPa/s 0.166
Process quality (1
–
0.166) x 100 83 %
Tab. 6 Example 1 for calculation of the process quality
Example 2
– Hysteresis – 5 kPa = 25 kPa
– Leakage time = 2 s
Value Calculation Result
VDR 25 kPa
-
2 s 12.5 kPa/s
Reference to 50 kPa/s (VDR) 12.5 kPa/s
-
50 kPa/s 0.25
Process quality (1
–
0.25) x 100 75 %
Tab. 7 Example 2 for calculation of the process quality
Function
13 Festo — VABF-S4-...-CB-VH/VL-... — 2019-05